This invention relates generally to lasers, and, more particularly to a gas laser which is extremely compact, lightweight and produces an exceptionally high power output.
Since the development of the first working lasers, considerable time and effort has been expended in the search for lightweight, compact, high output laser systems. The possible applications of such high power lasers are unlimited in the fields of communication, manufacturing and medicine. In particular, in the field of medicine and communication it is of utmost importance that the laser be lightweight and still produce high output.
Generally, the gas laser, and in particular, the CO.sub.2 laser has been largely used in the above applications. Unfortunately, even though the gas laser produces a high output, there are many problems relating to its use. For example, the gas laser fails to be as compact and lightweight as required. Since it is essential within satellites, for example, that a laser utilized for communications does not add to the overall weight of the satellite, much research in this field is still underway. Furthermore, in the field of medicine which requires hand-held portable laser devices that are capable of providing precision and "bloodless" cutting, the basic gas laser still leaves much to be desired.
Overcoming many of the problems associated with the conventional gas laser as described hereinabove, is a laser which is more commonly known as a waveguide gas laser. The waveguide gas laser incorporates therein a resonator in which radiation is transmitted in part by guided wave (or more precisely a low loss leaky wave) propagation rather than by free space propagation. In other words, the waveguide laser is a laser which employs an optical resonator surrounding a waveguide to provide the necessary feedback to establish oscillation. This is in contrast to a conventional laser where the feedback and resonator modes are established by normal free space propagation, resulting in the well known Gaussian normal mode.
As pointed out in an article by Richard L. Abrams entitled "Waveguide Gas Lasers," Laser Handbook, vol, 3, pub. North Holland, 1979, since the power output per unit length and efficiency of most waveguide laser systems is independent of discharge diameter, these lasers give identical performance to conventional lasers. Consequently, the advantages to be gained over conventional lasers include: reduced laser size to smaller transverse dimensions; higher laser gain in doppler broadened lasers resulting in the potential for compact, low power lasers otherwise not possible; high pressure operations resulting in potential increased frequency tunability in molecular lasers such as CO.sub.2 ; efficient matching between mode volume and laser excitation region; and, excellent mode control through the unique properties of waveguide laser resonators.
An example of an early form of a waveguide gas laser can be found in U.S. Pat. No. 3,772,611 issued Nov. 13, 1973. A greatly improved high power, compact waveguide gas laser is described in this inventor's U.S. Pat. No. 4,103,255 issued July 25, 1978.
The major drawback associated with the waveguide gas laser is that the waveguide laser has a limitation in its minimal transverse dimension in that it is incapable of operation if the waveguide resonator is sized below the waveguide mode of operation dimension, of, for example, 100 .mu.'s. In addition, it is essential for waveguide laser operation that the waveguide resonator or channel be exceptionally straight. Any variance in the straightness thereof can void the laser operation.
Therefore, it is extremely desirable to produce a high pressure, high power, compact laser which incorporates therein all the advantages of the conventional gas laser or, more particularly, the waveguide gas laser, and yet eliminates the disadvantages associated therewith.